By the Light of the Sun

After four hurricanes passed through Florida in 2004, leaving a tangle of downed power lines and outages, the most reliable power source proved to be solar.

When Katrina wreaked havoc in Louisiana and the Gulf Coast, solar may have been the quickest and most reliable way to restore power to the homes and businesses almost immediately after the storm.

Solar energy is growing in popularity and being seen as a real solution to power reliability problems. Photovoltaic (PV) solar power tied into integrated building systems (IBS), homes and utility sites is growing at a rate of 35 percent a year and has been for the past decade, according to Brad Collins, executive director of the American Solar Energy Society. “It’s on the verge of exploding,” he said.

There are several factors that could cause or hinder that explosion. The Energy Policy Act of 2005 offers tax credit for solar investments through 2007. If Congress were to pass a tax incentive extension, enough customers might decide to invest, dropping the cost of solar products, Collins said.

Reliability of solar power

After the hurricanes of 2004, the Florida Solar Energy Center investigated more than 20 solar panels in hard-hit areas across the state and found that they survived the storm better than most other building material. According to Charlie Cromer, Ph.D., interim director for photovoltaic division, “They were all in good operating condition. As long as the roof was still standing, the PV panels were still in working condition.”

In fact, Cromer said, they found that shingles were stripped off roofs everywhere but those located under PV panels were undisturbed.

In response, Florida launched a Solar in Schools program in 2005, installing PV panels statewide on schools that serve as hurricane shelters. This ensures that, in a disaster, solar power will still generate electricity for refugees inside. In the meantime, the schools use power produced by the panels, and a curriculum includes educating students about how solar energy works.

“We are pursuing additional applications of these over shelters with battery-backup supply,” Cromer said.

According to the American Solar Energy Society, the energy payback time for PV systems is two to five years. Considering that a well-designed and properly maintained PV system will operate beyond 20 years, and a system with no moving parts will operate up to 30 years, PV systems produce far more energy than is used in its manufacture.

In addition, consumers in 34 states can install small, grid-connected renewable energy systems to reduce their electricity bills using a protocol called net metering. With net metering, electricity produced by the solar PV panels can flow directly into the utility grid, spinning the existing electricity meter backward. This gives end-users a standardized protocol for connecting their solar systems into the electricity grid that ensures safety and power quality.

With incentives and better technology, clean energy markets grew to $40 billion in 2005 and are expected to reach $167 billion by 2015, according to a report from Clean Edge Inc., a clean technology research and publishing firm.

The best solar opportunity lies where the sun shines the most—in the southwestern United States. Not only does the sun generate solar power, it also creates the need for it. There is a correlation between electric power demand—in air conditioning—and the power provided through the same sun. In fact, Solar Electric Generating System plants operate for nearly 100 percent of the on-peak hours of Southern California Edison.

On a broader scale, IBS can help reduce the enormous amount of energy consumed across the United States by commercial buildings. Integrated building systems with solar PV panels can cut energy use by 50 percent or more, lower maintenance and capital costs, and also reduce environmental impact, according to a Department of Energy study.

IBS do not need to be more expensive to construct. However, they do require considerably more planning and teamwork among designers, engineers and contractors. Design teams with solar experience know that they must work together from the beginning of the design process. The building design team usually consists of architects, engineers, building owners and occupants, and specialists in areas such as indoor air quality, materials and energy use.

For commercial buildings, it is essential to bring energy consultants into the design process from the beginning and keep them involved throughout the process so they can advise owners of how changes to design will affect a building’s energy performance.

Forming a strong alliance

Sierra Electric Co. Inc., San Francisco, has begun working with solar power in several IBS systems. Most recently they installed PV panels at the Moscone Center in San Francisco, which produce 675 kilowatts during peak hours. In this case, they were subcontractors to PowerLight Solar Electric Systems, a Bay Area solar company that did the design work. Sierra Electric also installed a 230-kilowatt alternating current solar array on the roof of the Southeast Water Pollution Control Plant, San Francisco. In this case, for the design/build project, Sierra Electric used PowerLight as the subcontractor to do the design work.

“We’re trying to get in there and learn what the solar game is about,” said Matt Sullivan, Sierra Electric general manager.

The installation is straightforward, but designing is a new area for many electrical contractors, despite the growing market.

“There definitely are barriers to any contractor,” Sullivan said. “It’s new. When you walk into a standard office building, you know immediately what’s needed. But solar is still emerging.We’re taking baby steps toward taking on a project ourselves.”

In the meantime, alliances with companies such as PowerLight are a good alternative.

“I think the key for a ... contractor is having alliances with designers. Any good ... contractor could figure out how to install PV panels,” he said.

State and federal incentives

Solar has not been an easy sell in some areas. In New Mexico, for example, solar energy amounts to less than 100 kilowatt-hours of grid-connected power, according to Renewable Energy Access, with a majority of solar installations off the grid.

New Mexico and its neighboring states may be poised for a big change, as the state and federal incentives make solar increasingly desirable. A combination of newly established incentives and programs are now offering everything from a $9,000 tax credit to performance-based rebate tariffs up to 20 cents per kilowatt-hour. Some of the most active states in solar power are California and New Jersey, according to Andy Walker, senior engineer at National Renewable Energy Laboratory (NREL).

“Large commercial buildings have been a large portion of the market with systems connected into the grid,” he said.

Walker sees prices dropping while the Department of Energy’s goal of 50 cents per watt comes closer to reality. Efficiency should also improve, he said, with about 30 percent yield expected in the near future, while 16 percent is now average.

Although installation is fairly straightforward, safety is an issue.

“PV panels are energized when the sun is shining. So as soon as they come out of the box there will be voltage on their terminals,” Walker said.

IEEE standard 929 and UL 1741 address solar panel installation as well as National Electrical Code sections 690 and 720.

Some manufacturers intend solar installation to become even easier. In the near future, it may be a matter of a stop at Home Depot or Lowe’s and some simple installation. OrionSolar Photovoltaics Ltd., Israel, a PV developer, has created a photovoltaic solar energy cell that reduces the cost of producing solar electricity with polycrystalline silicon photovoltaic cells by more than 50 percent.

“We believe this technology will be installed as a do-it-yourself,” said OrionSolar CEO David Waimann. “Either you install it yourself if you are qualified, or you go to your local electrical contractor.”

“It can be used for offices, large apartments or even homes,” said Waimann. “It would be worthwhile for anyone with a large flat roof in states with decent subsidies.”

Waimann said the new panels are likely to be available in Asia first, but would arrive in the United States in the next few years.

Another alternative is solar electric systems purchased for emergency backup power, which operate off batteries and are not connected to the utility grid. Energy is captured in solar panels on the roof and transferred to batteries that store the power so that it is available when needed during power outages.

Although a solar system intended for emergency backup power can be more expensive, the potential savings, especially if power outages can be avoided, easily outweigh the higher initial system cost.

System costs can also be reduced significantly if business owners reduce the energy consumption of existing buildings through energy efficiency or design new buildings as low-energy-using commercial buildings. EC